With the rapid development of wireless communication technology, a wireless terminal such as a mobile terminal or a data card has been applied widely. Meanwhile, electromagnetic radiation effect of the wireless terminal on the human body has been gradually paid more attention. At present, an index measuring the electromagnetic radiation of an antenna to the human body is an SAR, which refers to a specific value of electromagnetic wave energy absorption of a wireless terminal. The meaning of the SAR is “electromagnetic energy absorbed by a unit mass of a biological tissue in a unit time”, with the unit of W/kg or mW/g. The Federal Communication Commission (FCC) explicitly stipulates maximum allowable SARs of various wireless terminals when these wireless terminals interact with a human body, and stipulates that the SAR of a mobile-phone-type mobile terminal should be measured when the mobile terminal is close to one side of a human brain and that the SAR of data-card-type terminal must be measured on four human-body surfaces near the data card. Thus, it has become an important problem to be solved in the industry that the radiation to the human body is reduced effectively while communication quality and miniaturization portability of the wireless terminal are ensured.
While the radiation effect of the mobile terminal on the human body is considered, a reaction of the human body on the mobile terminal must also be considered since a proximity effect of the human body may cause reduction of communication quality. Generally, when the human body is close to the mobile terminal, the human body, as a lossy conducting medium, will significantly affect a radiation characteristic of a terminal antenna. The affection may specifically include mismatch of antenna feed ports, reduction of a total radiation power caused by human body absorption and the like. At present, a main method for solving a reaction effect of the human body on the mobile terminal is generally to counteract antenna mismatch due to the human body through a matching network. Although the method can reduce mismatch loss on a radio-frequency circuit, this may result in more electromagnetic energy entering into the human body and further increase the SAR peak value.